U.S. Pat. No. 5,305,499 discloses a clamp formed from a band. The open clamp, which in the delivery condition is circularly pre-shaped, is placed around the object to be clamped with the two band end portions overlapping one another. For closing the clamp, hooks are provided in the overlapped inner band end portion, which engage apertures provided in the outer band end portion. The clamp is subsequently tightened by narrowing a so-called “Oetiker ear”.
The known clamp has three hooks. One of the hooks is a guide hook in the form of a tab bent from the band material to extend through a slot provided in the outer band end portion and extending in the longitudinal direction of the band. The two other hooks are support hooks, stamped out of the inner band end portion by cold deformation, to engage corresponding edges of window-shaped apertures in the outer band end portion. The edge of the guide hook, remote from the inner band end, extends obliquely outward so that, when the clamp is tightened, the mutually overlapping band end portions are guided toward each other and are maintained in a close overlapping relationship.
The tensile forces, which occur between the two band end portions in the tightened condition of the clamp, are transmitted primarily from the two support hooks formed at the inner band end portion onto the edges of the window-shaped apertures formed in the outer band end portion remote from the tightening means. It has been found that, when the tensile forces to be transmitted are increased, material failure will occur at these aperture or window edges.
U.S. Pat. No. 5,138,747 discloses a hose clamp which has an elasticity reserve in the form of an attached spring and an additional means for limiting the force acting on the spring. This limiting means uses a hook that engages the edge of an aperture at the given maximum force.